WO2021058355A1

WO2021058355A1 - Casing unit and steering column for a motor vehicle

Info

Publication number: WO2021058355A1
Application number: PCT/EP2020/075918
Authority: WO
Inventors: Hieronymus Schnitzer; Hansjoerg Sulser
Original assignee: Thyssenkrupp Presta Ag; Thyssenkrupp Ag
Priority date: 2019-09-24
Filing date: 2020-09-16
Publication date: 2021-04-01
Also published as: EP4034451A1; DE102019214557A1

Abstract

The present invention relates to a casing unit for an adjustable steering column for a motor vehicle, comprising an inner casing pipe (4), which extends axially in the direction of a longitudinal axis and comprises a clamping portion (41) having a non-round outer cross section and, in an end region, comprises at least one bearing portion (42) having a circular cylindrical inner cross section, and an outer ring (71) of a rolling bearing is received in the bearing portion (42), which outer ring has rolling bodies (76) which can roll between a track of the outer ring (71) and a track of an inner ring (74), wherein a steering shaft (31) can be received in in the inner ring (74). In order to enable a construction having high stiffness which is simple to produce, reliable and compact, according to the invention the rolling bodies (76) are arranged axially offset relative to the bearing portion (42). Furthermore, the invention relates to a steering column having such a casing unit and to a method for producing such a casing unit.

Description

l

Jacket unit and steering column for a motor vehicle

State of the art

The invention relates to an adjustable steering column for a motor vehicle, comprising an inner casing tube which extends axially in the direction of a longitudinal axis and has a Klemmab section with a non-circular outer cross-section and in an end region at least one Lagerab section with a circular cylindrical inner cross-section, and an outer ring in the bearing section a roller bearing is received, the ring between a raceway of the outer ring and a raceway of an inner ring has rollable rolling elements, wherein a steering shaft can be received in the inner ring. A steering column with such a jacket unit is also the subject of the invention.

The steering column of a motor vehicle comprises a steering shaft, on the driver-side, rear end of the steering shaft in the direction of travel, a steering wheel for inputting steering commands is mounted. The steering shaft is rotatably mounted about its longitudinal axis in a jacket unit. For mounting in a motor vehicle, the jacket unit is held by a support unit which is connected to the body. In the case of an adjustable steering column, the jacket unit is designed to be axially adjustable for longitudinal adjustment to adapt to the driver's position, i.e. telescopically adjustable in the direction of the longitudinal axis. For this purpose, the jacket unit has an inner jacket tube in which the steering shaft of the generic design is rotatably mounted in at least one roller bearing. The inner jacket tube is axially adjustable in an outer jacket that is held by the support unit. By means of a Spanneinrich device, which can be brought into a fixing position or a release position either manually or by motor, the outer jacket can be clamped outside on a Klemmab section of the inner jacket in the fixing position, so that it is fixed in the longitudinal direction. In the release position, the tension is released, so that the inner jacket can be adjusted together with the steering shaft section having the steering wheel in the longitudinal direction forwards towards the outer jacket or backwards away from the outer jacket.

From EP 2 711 265 A1 an inner jacket tube for a jacket unit is described, wel Ches has a clamping portion with a polygonal outer cross-section, on which an internally circular cylindrical bearing portion is attached to the rear end region. The circular cylindrical internal cross-section extends from an end face over the width of the bearing section axially in the direction of the clamping section. The outer ring can be in the bearing section Rolling bearings are used and fixed, for example by axial pressing. In the nenring is mounted for rotatable mounting on the steering shaft.

The bracing of the outer jacket can take place from the outside against the clamping or contact surfaces of the inner jacket tube. For example, side cheeks of the support unit can be clamped against lateral clamping surfaces of the inner jacket tube by means of the clamping device, or a type of clamp or the like that encompasses the inner jacket tube can be formed. In order to be able to realize the largest possible axial adjustment range, the circular cylindrical bearing section is provided on its outer circumference with umgeform th areas in order to extend the clamping surfaces axially into the area of the bearing section.

The disadvantage of the aforementioned inner jacket tube is the high machining effort required. In addition, in the most unfavorable case, an asymmetrical radial force can be exerted on the outer ring of the roller bearing in the fixing position due to the bracing of the outer jacket in the bearing section. In order to avoid these disadvantages, an axial lengthening of the bearing section would be possible, but this is not acceptable because of the associated increase in installation space and the reduction in rigidity.

In view of the problems explained above, it is an object of the present invention to provide an improved jacket unit which enables a more easily manufactured, operationally reliable and compact design with high rigidity.

Presentation of the invention

This object is achieved according to the invention by a jacket unit having the features of claim 1 and a steering column according to claim 11 comprising such a jacket unit. Advantageous further developments result from the subclaims.

In a jacket unit for an adjustable steering column for a motor vehicle, comprising an inner jacket tube which extends axially in the direction of a longitudinal axis and has a Klem m section with a non-circular outer cross-section and in one end region at least one bearing section with a circular cylindrical inner cross-section, and in the Lagerab section Outer ring of a rolling bearing is received, which has between a raceway of the outer ring and a raceway of an inner ring rollable rolling elements, wherein a steering shaft can be received in the inner ring, it is provided according to the invention that the rolling elements are arranged axially offset to the bearing section. The outer ring is preferably received in the bearing section in such a way that the bearing ring is supported radially, that is to say in a direction orthogonal to the longitudinal axis, that is to say is borne by it. It is thus possible to speak of a fixation of the outer ring in the radial direction. Particularly preferably, the outer ring is also cut in the axial direction in the Lagerab, fixed at least in one direction.

Preferably, the rolling elements are axially offset in the direction of the clamping portion is arranged.

The clamping section can preferably be received in an axially guidable manner in an outer jacket and can be clamped in this for fixing in the axial direction.

The bearing section is rich in at least one, preferably at least the front Endbe, arranged the end region of the inner jacket tube facing the front of the vehicle. The circular cylindrical inner cross-section extends accordingly from the end face of the inner jacket tube axially in the direction of the clamping section. In other words, the bearing section is arranged at the end between the clamping section and the end face. The width of the bearing section, hereinafter also referred to as bearing width for short, denotes, according to definition, the axial extent of the circular-cylindrical inner cross-section.

According to the invention, the rolling elements are positioned axially offset relative to the circular cylindrical inner cross-section of the bearing section, namely in NEN when viewed from the end face, that is to say closer to the clamping section. The axially offset arrangement means that the contact area of the rolling elements with the raceway of the outer ring is outside the bearing section in which the outer ring is connected via its outer surface to the circular cylindrical inner surface of the bearing section. This can be achieved in that the contact area of the rolling elements, measured from the end face, has a distance which is greater than the axial width of the bearing section, specifically the bearing width of the circular-cylindrical inner surface. The contact area is preferably outside the bearing section, the contact area preferably being axially spaced from the bearing section. At least, however, the rolling elements are predominantly located outside the bearing section, so that at least the contact area with a larger sub-area is accordingly arranged outside the circular-cylindrical inner cross section of the bearing section.

One advantage of the invention is that the bearing section can have a smaller axial width, that is to say can be designed to be narrower than in the prior art. This allows a rela- tively short installation space can be realized without the clamping surfaces having to be extended into the bearing section, as in the prior art. Accordingly, the manufacturing effort for the inner jacket tube and thus for the jacket unit and the steering column can be reduced.

Another advantage is that the transverse forces applied from the outside to the outer ring of the rolling bearing from the outside during assembly and during operation no longer act radially in the area of the rolling elements, but rather from the raceway due to the axially ver set arrangement to a certain extent can be decoupled. This can simplify production and increase operational reliability. Another advantage over the prior art is that the bearing section has a groove-free internal cross-section so that the bearing can be accommodated in it in an improved manner.

Due to the staggered arrangement, a high rigidity of the bearing arrangement can still be achieved, whereby a sufficiently high rigidity of the jacket unit and thus of the steering column in the longitudinal direction to the maximum extent of the adjustment state is guaranteed.

An advantageous embodiment is that the rolling bodies have balls, the ball center point of which is axially spaced from the bearing section. Accordingly, the roller bearing is designed as a ball bearing. If the bearing portion extends from the end face and has an axial width, which is also referred to as the bearing width, the axial distance of the ball center point from the end face, which is referred to as the ball distance, is greater than the La gerbreite. Each ball touches the raceway, depending on the raceway cross-section, at one or two points in a small, almost punctiform contact point. These contact points can preferably lie at least on the raceway of the outer ring axially spaced from the bearing section.

It is preferably provided that the distance between the center of the sphere and the bearing section is at least 1 mm, preferably at least 2 mm. The distance between the center point of the Ku and the bearing section is preferably at least the radius of the sphere. The outer diameter of the outer ring, which essentially corresponds to the inner diameter of the circular cylindrical inner cross section, can usually be between 20 mm and 50 mm, consequently it is advantageous if the ratio between the distance between the center of the sphere and the bearing section and the diameter of the bearing section is at least between Is 1:10 and 1:50, particularly preferably between 1:20 and 1:40. As a result, a short overall length and a high degree of rigidity can be achieved before geous. It can be advantageous for the raceway of the outer ring and / or the raceway of the inner ring to be arranged offset from the bearing section. The raceway can follow the cylindrical inner cross-section axially in the direction of the clamping section, that is, it can be arranged behind the bearing section as seen from the end face, preferably at a distance from it axially. As a result, the contact surfaces of the rolling elements with the outer ring, for example the contact points of the balls, are in any case axially outside the bearing section, preferably axially spaced from it.

For the load absorption and the operating properties, it can be advantageous that the bearing is designed as an angular contact ball bearing. The connecting line between the contact points of a ball with the raceway of the inner ring and the raceway of the outer ring does not run radially, i.e. perpendicular to the longitudinal axis, but at an angle to it. It is preferred that the connecting line intersects the longitudinal axis at an acute angle which opens from the bearing section, i.e. viewed from the end face, towards the clamping section. This can be achieved in that the contact point of a ball with the raceway of the outer ring is axially further spaced from the bearing section than the contact point of the ball on the outside of the raceway of the inner ring.

An advantageous embodiment of the invention provides that the rolling elements and / or the raceway of the outer ring and / or the raceway of the inner ring are predominantly positioned within the clamping section. The clamping section can adjoin the bearing section in the axial direction from the end face, it being possible for an axial distance to be provided or not. “Predominantly within” means that a larger partial area of the rolling element cross-section is arranged in the clamping section than in the bearing section. In the case of a ball as a rolling element, at least the center of the ball can be located axially outside the bearing section and inside the clamping section. The contact point or area of a rolling element with the raceway to at least the outer ring is also preferably located axially within the clamping section. This configuration is advantageous for a compact design and high rigidity.

In an advantageous embodiment it can be provided that the outer ring has radial play to the inside of the inner jacket tube in the area of its raceway. This can be achieved in that the clamping section has a larger inner cross section than the bearing, and alternatively or additionally the outer ring in the area of the bearing section has a larger outer diameter or outer cross section than in the area of the Klemmab section, where according to the invention the rolling elements are positioned in the raceway . In the area a circumferential annular gap can be formed between the outer ring and the inner surface of the raceway. This allows the radial load on the bearing to be optimized.

It can be provided that the outer ring is axially equal to or wider than the Lagerab section. Correspondingly, the roller bearing is only received over part of its axial width (outer ring width or roller bearing width) in the inner cylindrical bearing section and is fixed to it. When the outer ring ends flush with the end face of the inner jacket tube, the outer ring can vorste from the bearing section to the clamping section and extend axially into the clamping section. By positioning the raceway, the arrangement of the rolling elements according to the invention can be implemented with little effort.

It is an advantageous embodiment that the outer ring has a holding section that can be accepted in the bearing section and a track section in which the track is formed. The holding section is preferably cylindrical on the outside and designed and measured for non-positive, positive and / or cohesive fixation in the inner cylinder of the bearing section, for example by being axially pressed in. The axial width of the holding section is preferably adapted to the width of the bearing section, preferably essentially the same, but it is also conceivable and possible that this is shorter than the bearing section. The track section adjoining the holding section in the axial direction is located axially outside the bearing section in the assembled state and can protrude axially from the bearing section into the clamping section when viewed from the end face. As a result, according to the invention, the raceway and the rolling bodies arranged therein are arranged offset in the direction of the clamping section relative to the bearing section. The holding and raceway sections are preferably formed in the case of an outer ring which has an outer ring width that is greater than the width of the bearing. For assembly with the outer ring, the bearing can be pressed axially into the bearing section until the holding section is flush with the end face and the raceway with the rolling elements is positioned outside the bearing section.

It can be advantageous for the outer ring in the raceway section to have a smaller outer diameter than in the holding section. The fact that the outer diameter of the preferably circular-cylindrical holding section is adapted for connection to the circular-cylindrical bearing section, and the raceway section has a relatively smaller diameter, means that radial play is formed in the raceway section with respect to the inner sleeve. As a result, the advantages described above can be achieved with little effort. The clamping section can preferably have a polygonal cross section with clamping surfaces which are opposite transversely to the longitudinal axis and can be braced with an outer jacket. For example, the clamping section can be designed at least in sections as an octagonal, hexagonal or square tube, preferably as an octagonal tube with an octagonal cross section. In such pipe cross-sections with even-numbered sides, two outer surfaces opposite the longitudinal axis in pairs can serve as clamping surfaces, between which the inner jacket pipe can be clamped by applying a clamping force transverse to the longitudinal axis between the inner sides of the outer jacket to fix a set adjustment position.

The inner jacket tube can preferably be designed as a shaped sheet metal part, preferably made of sheet steel, wherein the clamping section and at least one Lagerab section according to the invention are integrally formed in a bent shaped part. Production is possible with less effort than in the cited prior art, in which additional forming operations are required to form the clamping surfaces in the bearing section.

The invention further comprises a steering column comprising a jacket unit with an inner jacket tube in which a steering shaft is rotatably mounted about a longitudinal axis and which is held in an outer jacket that can be connected directly or indirectly to the body of a motor vehicle and with which a clamping device cooperates , which can be brought into a fixing position and a release position, wherein in the fixing position the inner jacket tube is clamped in the outer jacket, and in the release position the inner jacket tube is adjustable in the outer jacket in the longitudinal direction, wherein according to the invention the jacket unit can be configured as explained above. The features described can be implemented individually or in any combination.

The jacket unit can be attachable to a body of a motor vehicle by means of a support unit. The support unit can, as is known per se, have one or two protruding side cheeks on which or between which the outer jacket can be clamped and released by means of a clamping device for adjustment. The inventive configuration, a longitudinal adjustment, ie an axial adjustment of the inner jacket tube relative to the outer jacket tube with the advantages described above can be realized who the. It is also conceivable and possible to attach the jacket unit to the support unit in a height-adjustable manner. For this purpose, the jacket unit can be articulated on the support unit so as to be pivotable in the vertical direction about a pivot axis lying horizontally transversely to the longitudinal axis, whereby a releasable bracing with the support unit can take place by means of the clamping device. A section of the steering shaft, which is preferably designed as a variable-length steering spindle, is mounted rotatably about the longitudinal axis in the jacket unit. A variable-length shaft arrangement known per se can be used, for example with telescopically axially adjustable splined shafts or non-circular shafts, in each of which an inner shaft with a round cross-section engages axially displaceably in a corresponding inner cross-section of a hollow or outer shaft. For example, the inner or outer shaft can be mounted in a bearing arrangement according to the invention at the front end, with which the inner casing tube dips into the outer casing. In the rear, lenkradseiti gene end region of the inner jacket tube, the steering spindle can be mounted in a second Lageranord voltage, which can also have a roller bearing. There is usually more installation space available, and when locking the steering column by means of the Spannvorrich device there is usually no clamping force in the bearing section. Therefore, a wider bearing section can be realized.

The invention further comprises a method for producing a jacket unit of the type described above, comprising an inner jacket tube which extends axially in the direction of a longitudinal axis and has a clamping section with a non-circular outer cross section and in an end region at least one bearing section with a circular cylindrical inner cross section, and in an outer ring of a roller bearing is accommodated in the bearing section, which has between a raceway of the outer ring and a raceway of an inner ring rollable rolling elements, wherein a steering shaft can be accommodated in the inner ring, which provides the following steps:

- Provision of an inner jacket pipe blank, which is designed as a pipe section with an unrun cross section,

- Insertion of a cylindrical dome into the pipe section,

- Pressing an inner cylindrical ring die onto the pipe section in the area of the dome in such a way that at least one end section of the pipe section is plastically deformed in the space between the mandrel and the ring die to form a cylindrical bearing section,

- Insertion of an outer ring of a roller bearing into the bearing section,

- Introducing an inner ring into the outer ring, with rolling elements being arranged to roll between them.

For example, the inner jacket tube blank can be designed as a tube section of an octagonal, hexagonal or square tube, preferably as an octagonal tube with an octagonal cross section. In the clamping section, the inner jacket tube retains this non-circular cross section, so that the advantages described above can be realized. By the procedural Ren according to the invention, the non-circular cross-section is at least in one end area between the outside cylindrical Drischen mandrel and the inner cylindrical ring die plastically deformed to form a hollow cylindrical bearing section in which an externally cylindrical bearing section can be optimally received. The mandrel preferably has an outer diameter like the Lagerab section, or slightly smaller, so that the inner diameter of the bearing section is undersized to the outer ring. This undersize can be specified in such a way that the outer ring can be fixed in the bearing section by pressing

One advantage of the method is that an inner jacket pipe blank can be made available from a readily available, inexpensive semi-finished product such as a polygonal pipe material simply by cutting it to length. One or more bearing sections can be created on this simply and efficiently by cold forming. As a result, an efficient and precise production is possible, and the inner jacket tube produced in this way in one piece has an advantageously high stiffness.

It is advantageous that the rolling elements are arranged axially offset with respect to the bearing section. For this purpose, the outer ring is axially fixed in the bearing section produced according to the invention, for example by pressing and / or positive or cohesive connections, preferably non-detachable, and the inner ring is axially offset to it on the outside of the steering spindle.

The raceway of the outer ring and / or the raceway of the inner ring can advantageously be arranged offset from the bearing section. The raceway can follow the cylindrical inner cross-section axially in the direction of the clamping section, i.e. behind the bearing section viewed from the end face, preferably at a distance from it axially. As a result, the contact surfaces of the rolling elements with the outer ring, for example the contact points of the balls, are in any case axially outside of the Lagerab section, preferably axially spaced from this.

By means of the method according to the invention, a jacket unit with the features described above and a steering column with such a jacket unit can advantageously be produced.

Description of the drawings ok

Advantageous embodiments of the invention are explained in more detail below with reference to the drawings. Show in detail:

Figure 1 shows a steering column according to the invention in a schematic perspective

View,

Figure 2 shows the steering column according to Figure 1 in a further schematic perspective view,

FIG. 3 shows a longitudinal section through the steering column according to FIG. 1,

FIG. 4 shows a detailed view from FIG. 2 in the release position of the steering column,

FIG. 5 shows a detailed view as in FIG. 5 in the fixed position of the steering column,

FIG. 6 shows an inner jacket tube according to the invention of the steering column according to FIG. 1 in a schematic perspective view.

Embodiments of the invention

In the various figures, the same parts are always given the same reference numerals and are therefore usually only named or mentioned once.

Figures 1 and 2 show a steering column 1 in different perspective views, namely Figure 1 with respect to the installation position in the direction of travel obliquely from behind to the left side, and Figure 2 also from behind obliquely to the underside.

For mounting in the motor vehicle, the steering column 1 has a support unit 2 with fastening means 21 for connection to the body of the motor vehicle, not shown, for example fastening openings as shown.

In a jacket unit 3 according to the invention, a steering spindle 31, which represents the rear shaft part of the steering shaft with respect to the direction of travel, is mounted rotatably about its longitudinal axis L. At the rear end, the steering shaft 31 has a fastening portion 32 for attaching a steering wheel, not shown. The jacket unit 3 has an outer jacket 33 in which an inner jacket tube 4 is arranged coaxially and can be adjusted in the longitudinal direction, ie axially in relation to the longitudinal axis L, as indicated by the double arrow parallel to the longitudinal axis L. The Außenman tel 33 is formed similar to a pipe clamp in which the inner jacket pipe 4 is releasably fi xable, as will be explained.

The inner jacket tube 4 is shown separately in perspective in FIG. 6. The installation situation can be seen in the longitudinal section of Figure 3, which shows a view from above.

The jacket unit 3 is arranged with the outer jacket 33 between two with respect to the longitudinal axis L opposite side cheeks 22 and 23, which extend from the Tragein unit 2 downward.

On the side cheeks 22 and 23 engages a clamping device 5, which has a Spannbol zen 51, which is rotatably mounted transversely to the longitudinal axis L through elongated holes 24, which are formed in a height direction H in the side cheeks 22 and 23. An actuating lever 52 is rotatably connected to one end of the clamping bolt 51, wel Ches is supported from the outside on one side cheek 22 via a lifting gear 53. The lifting gear 53 can be designed in a known form as cam, wedge disks or Kippstiftge drives to convert a rotation of the clamping bolt 51 into an axial lifting movement which is directed from the outside against the side cheek 22. The other end of the clamping bolt 51 is supported rotatably, but with tensile strength from the outside against the other Seitenwan ge 23.

By rotating the clamping bolt 51 by manually actuating the operating lever

52, the clamping device 5 can be switched between a fixing position and a release position. In the fixing position, the clamping bolt 51 is actuated by the lifting gear

53 is drawn outwards relative to the side cheek 22, so that the side cheeks 22 are drawn together against one another, as is indicated in FIG. 1 with the arrows pointing towards one another. As a result, the outer jacket 33 is clamped between the side cheeks 22 and 23, so that the jacket unit 3 is clamped and fixed on the support unit 2. At the same time, the outer jacket 33, which closes the inner jacket pipe 4 like a pipe clamp, is braced on the inner jacket pipe 4 and fixed in the longitudinal direction. For adjustment, the clamping device 5 is brought into the release position by opposite manual rotation, wherein the clamping force exerted between the side cheeks 22 and 23 is released. As a result, the clamping axis 51 can be moved up or down in the elongated holes 24. The jacket unit 3 can be pivoted about the pivot axis S, which is arranged horizontally in its front area, in the height direction H for adjusting the height of the steering spindle 31, as indicated by the double arrow.

The bracing of the outer jacket 33 on the inner jacket tube 4 is also released, so that a longitudinal adjustment is made possible.

The inner jacket tube 4 has a central clamping section 41, which has a non-circular, in the example shown, octagonal tube cross-section. At the front end, which is directed to the left in FIG. 3 and dips into the outer casing 33, a first bearing section 42, which has a circular cylindrical inner cross section, is integrally formed with the clamping section 41 in one piece. Specifically, the bearing section 42 has a cylindrical tube section. At the other, rear or steering wheel-side end, a further hollow cylindrical bearing section 43 is arranged, likewise in one piece with the clamping section 41.

The illustration in FIG. 3 shows that the steering spindle 31 is designed as a variable-length shaft, that is, designed as a telescopic shaft with a hollow shaft 34, into which an inner shaft 35 is axially displaceable but torque-locked. The inner shaft 35 and the hollow shaft 34 can have korrespondie-generating non-circular cross-sections or longitudinal gears for torque transmission in a manner known per se.

In the bearing section 43, a bearing 6 is attached, preferably a roller bearing, in which the rear section of the steering spindle 31 is mounted, namely the hollow shaft 34. In particular, it is an angular roller bearing. The width of the bearing 6 in the axial direction can essentially correspond to the width of the bearing section 43.

In the front area, the hollow shaft 34 of the steering spindle 31 is mounted in a ball bearing 7, which is designed and arranged according to the invention, in the inner jacket tube 4. In the example shown, the ball bearing 7 is designed as an angular contact roller bearing, so that the bearing 7 and the bearing 6 form an angular contact ball bearing arrangement which form an O-arrangement. An X-arrangement would also be conceivable and possible. Furthermore, the design of the bearings 6 and 7 as radial deep groove ball bearings would also be conceivable. The teaching according to the invention with regard to the design of the bearing seat can thus be transferred to different bearing types and is not restricted to a single type.

An enlarged partial representation from FIG. 3 of the bearing 7 is shown in FIGS. 4 and 5, where FIG. 4 shows the release position and FIG. 5 shows the fixing position. The bearing 7 has an outer ring 71 which has an externally cylindrical holding section 72 and a raceway section 73 which is axially connected to it and which comprises the raceway of the outer ring 71. Furthermore, the bearing 7 has an inner ring 74, with an inner raceway section 75 which encompasses the raceway of the inner ring 74. The inner ring 74 is fixed on the hollow shaft 34 of the steering spindle 31. Between the mutually directed raceways, which umlau fen inside on the raceway section 73 and outside on the raceway section 75, balls 76 are arranged as rolling bodies, each having a center point K of the balls. The balls 76 each rest in almost point-shaped contact surfaces in the contact points P on the said raceways, the connecting line through the contact points P egg ner ball 76, which is indicated by dashed lines, is inclined to the radial direction, so that an angular contact ball bearing is formed.

The bearing portion 42 has an axial width B, measured from the end face of the Innenman telrohrs 4, which is preferably less than or equal to the width of the holding portion 72. Accordingly, the track section 75 is axially inward, offset in the direction of the clamping section 41. The balls 76 which can be rolled in the raceway of the raceway section 73 have measured an axial distance A from the end face of the inner jacket tube 4, which is greater than the width B of the bearing section, so that the rolling elements 76 are arranged offset according to the invention with respect to the bearing section. Accordingly, there are ball center points K outside of the bearing section 42, and are arranged offset relative to this in the direction of the Klem m section 41 to. The center of the sphere K is spaced apart from the bearing section 42 by the difference (A-B).

The balls 76 lie axially predominantly within the clamping section 41; in other words, the rolling bodies 76, which are designed as balls, lie axially predominantly within the bearing section 42.

FIG. 5 shows the same view as FIG. 4 in the fixing position. The clamping device 5 clamps the outer jacket 33 with the clamping force F from the outside against the clamping section 41 of the inner jacket tube 4, which can be seen from the fact that in Figure 5, in contrast to Figure 4, there is no radial play between the clamping section 41 and the outer jacket 33 exists.

Another advantage with regard to the introduction of force into the bearing 7 results from the fact that there is radial play X between the outer circumference of the raceway section 73 and the inner circumference of the inner casing tube 4. This can be achieved by the fact that the ßenring 71 has a smaller outer diameter in the raceway section 73 than in the holding section 72, and / or the inner jacket tube 4 has a larger inner diameter in the clamping section 41 than in the bearing section 42, with de possibilities being fulfilled in the example shown. Thanks to this measure, the fluctuations in the slipping torque of the steering shaft can be reduced, so that the fluctuations in the torque required for the rotation are significantly reduced over an entire revolution.

List of reference symbols

1 steering column

2 carrying unit

21 fasteners

3 jacket unit

31 steering shaft

32 mounting section

33 outer jacket

34 hollow shaft

35 inner shaft

4 inner jacket pipe

41 clamping section

42 Storage section

43 Storage section

5 clamping device

51 clamping bolts

52 operating lever

53 Tensioning Gear

6 rolling bearings

7 ball bearings

71 outer ring

72 holding section

73 career segment

74 inner ring

75 career segment

76 bullet

L longitudinal axis

H height direction

S swivel axis

K center of the sphere

P contact point

B width

A distance

F clamping force

X game

Claims

PATENT CLAIMS

1. Jacket unit (3) for an adjustable steering column (1) for a motor vehicle, comprising an inner jacket tube (4) which extends axially in the direction of a longitudinal axis (L) and a clamping portion (41) with a non-circular outer cross-section and in one end region at least has a bearing section (42) with a circular cylindrical inner cross-section, and in the bearing section (42) an outer ring (71) of a roller bearing (7) is received, which can roll between a raceway of the outer ring (71) and a raceway of an inner ring (74) Has rolling elements (76), wherein a steering shaft (31) can be received in the inner ring (74), characterized in that the rolling elements (76) are arranged axially offset to the bearing section (42).

2. Sheath unit according to claim 1, characterized in that the rolling elements have Ku rules (76) whose ball center (K) is axially spaced from the bearing section (42).

3. Sheath unit according to claim 2, characterized in that the distance of the Ku gelmittelpunkts (K) from the bearing portion (42) is at least 1 mm.

4. Sheath unit according to one of the preceding claims, characterized in that the raceway of the outer ring (71) and / or the raceway of the inner ring (74) is arranged offset from the bearing section (42).

5. Jacket unit according to one of the preceding claims, characterized in that the rolling elements (76) and / or the raceway of the outer ring (71) and / or the raceway of the inner ring (74) are positioned predominantly within the clamping portion (41).

6. Jacket unit according to one of the preceding claims, characterized in that the outer ring (71) in the region of its raceway has radial play (X) to the inside of the inner jacket tube (4).

7. Jacket unit according to one of the preceding claims, characterized in that the outer ring (71) is axially equal to or wider than the bearing section (42).

8. Jacket unit according to one of the preceding claims, characterized in that the outer ring (71) has a in the bearing portion (42) receivable Halteab section (72) and a track portion (73) in which the track is out forms.

9. Sheath unit according to claim 8, characterized in that the outer ring (71) in the raceway section (73) has a smaller outer diameter than in the Hal teabschnitt (72).

10. Sheath unit according to one of the preceding claims, characterized in that the clamping section (41) has a polygonal cross section with opposite clamping surfaces transversely to the longitudinal axis (L) and which can be braced with an outer jacket (33).

11. Steering column (1) comprising a jacket unit (3) with an inner jacket tube (4) in which a steering shaft (31) is rotatably mounted about a longitudinal axis (L) and which can be connected directly or indirectly to the body of a motor vehicle Outer jacket (33) is supported, with which a clamping device (5) cooperates, which can be brought into a fixing position and a release position, the inner jacket tube (4) being clamped in the outer jacket (33) in the fixing position, and the release position Inner jacket pipe (4) is adjustable in the outer jacket (33) in the longitudinal direction, characterized in that the jacket unit (3) is designed according to one of claims 1 to 10.

12. A method for producing a jacket unit (3) according to any one of claims 1 to 10, comprising an inner jacket tube (4) which extends axially in the direction of a longitudinal axis (L) and a clamping portion (41) with a non-circular outer cross-section and at least in one end region has a bearing section (42) with a circular cylindrical inner cross-section, and in the bearing section (42) an outer ring (71) of a roller bearing (7) is received, the rolling elements rollable between a raceway of the outer ring (71) and a raceway of an inner ring (74) (76), wherein a steering shaft (31) can be received in the inner ring (74), characterized in that

- Provision of an inner jacket pipe blank, which is designed as a pipe section with a non-circular cross-section,

- Insertion of a cylindrical dome into the pipe section,

- Pressing an inner cylindrical ring die onto the pipe section in the area of the dome in such a way that at least one end section of the pipe section is plastically deformed in the intermediate space between the mandrel and the annular die to form a cylindrical bearing section (42),

- Insertion of an outer ring (71) of a roller bearing into the bearing section (42), - Insertion of an inner ring (74) into the outer ring (71), with rolling elements (76) being arranged between them such that they can roll off.

13. The method according to claim 12, characterized in that the rolling elements (76) are arranged axi al offset to the bearing section (42).